U.S. patent number 6,324,925 [Application Number 09/701,002] was granted by the patent office on 2001-12-04 for suction device with means for removing a replaceable tip.
This patent grant is currently assigned to Biohit Oyj. Invention is credited to Pertti Ekholm, Osmo Suovaniemi.
United States Patent |
6,324,925 |
Suovaniemi , et al. |
December 4, 2001 |
Suction device with means for removing a replaceable tip
Abstract
A method for removing a replaceable tip used with a suction
device for dispensing a liquid removes the tip by bringing a
removal device, arranged in an air space formed jointly by a sample
space of a replaceable tip and a cylindrical space of an end part
of a suction device, movable between its two extreme positions,
namely an inner home position and an outer removal position, into
cooperation with an inside surface of the replaceable tip mounted
on the end part whereby the movement of the removal device into its
removal position causes the replaceable tip to be detached from the
end part. A suction device is provided for using the method.
Inventors: |
Suovaniemi; Osmo (Helsinki,
FI), Ekholm; Pertti (Helsinki, FI) |
Assignee: |
Biohit Oyj (Helsinki,
FI)
|
Family
ID: |
8551950 |
Appl.
No.: |
09/701,002 |
Filed: |
November 22, 2000 |
PCT
Filed: |
June 09, 1999 |
PCT No.: |
PCT/FI99/00499 |
371
Date: |
November 22, 2000 |
102(e)
Date: |
November 22, 2000 |
PCT
Pub. No.: |
WO99/64159 |
PCT
Pub. Date: |
December 16, 1999 |
Foreign Application Priority Data
Current U.S.
Class: |
73/864.14 |
Current CPC
Class: |
B01L
3/0279 (20130101) |
Current International
Class: |
B01L
3/02 (20060101); G01L 003/02 () |
Field of
Search: |
;73/864.01,864.11,864.13,864.14,864.16,864.24 ;422/100 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0155087 |
|
Sep 1985 |
|
EP |
|
WO9104793 |
|
Apr 1991 |
|
WO |
|
Primary Examiner: Raevis; Robert
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch, LLP
Parent Case Text
This application is the national phase under 35 U.S.C. .sctn.371 of
PCT International Application No. PCT/FI99/00499 which has an
International filing date of Jun. 9, 1999, which designated the
United States of America.
Claims
What is claimed is:
1. A method for removing a replaceable tip which encloses a sample
space, the replaceable tip being useable in a suction device for
dispensing, transferring, diluting, titrating, or mixing a liquid,
the suction device having an end part enclosing a cylindrical space
with a reciprocating piston for changing volume of the cylindrical
space, the replaceable tip being fitted on an outside surface of
the end part, the method comprising the steps of removing the tip
with a removal device, the removal device being mounted in an air
space formed jointly by the sample space of the replaceable tip and
the cylindrical space of the end part of the suction device, moving
the removal device between an inner home position and an outer
removal position, the removal device being moved into contact with
an inside surface or into contact with projections, pegs or ribs
associated with the inside surface of the replaceable tip, whereby
movement of the removal device into the outer removal position
detaches the replaceable tip from the end part.
2. The method according to claim 1, wherein the movement of the
removal device to the outer removal position is brought about by
the movement of the piston moving reciprocatingly in the
cylindrical space of the end part of the suction device and
provided for changing the volume of the cylindrical space.
3. The method according to claim 1, wherein the end of the piston
is brought into contact with the removal device.
4. The method according to claim 1, wherein the removal device is
removed from the end part by movement of the piston provided for
changing the volume of the cylindrical space.
5. The method according to claim 1, wherein the removal device is
removed from the end part together with the detachable replaceable
tip.
6. The method according to claim 1, wherein the removal device is
returned to the home position by a compression spring.
7. A suction device for dispensing, transferring, diluting,
titrating, or mixing a liquid, the device comprising an end part
and a replaceable tip with a sample space being fitted on an outer
surface of the end part, the end part enclosing a cylindrical space
having a reciprocating piston for changing volume of the
cylindrical space, the end part being provided with an aperture in
an extremity thereof in order to form a gas passage between the
sample space of the replaceable tip and the cylindrical space of
the suction device, the suction device further comprising means for
removing the replaceable tip, the removal means being arranged to
move at least partially in the cylindrical space of the end part of
the suction device between an inner home position and an outer
removal position where the removal means comes into contact with
the inside surface or into contact with projections, pegs or ribs
on the inside surface of the replaceable tip and thereafter pushes
the replaceable tip from the end part.
8. The suction device according to claim 7, wherein the removal
means is arranged in the removal position to extend out of the
aperture of the end part into the sample space of the replaceable
tip attachable onto the end of the end part for removing the
replaceable tip from the end part.
9. The suction device according to claim 7, wherein the end part is
provided with a compression spring for returning the removal means
to the home position.
10. The suction device according to claim 7, wherein the piston and
the removal means each have a common longitudinal axis and wherein
for a first position, the piston and the removal means are at a
distance from each other along their longitudinal axes, the first
position being at least one sample handling position and wherein
for a second position, the piston contact the removal means in
order to push the removal means to the removal position whereby the
replaceable tip is detached from the end part.
11. The suction device according to claim 7, wherein at least one
of the removal means and the end of the removal means nearest to
the replaceable tip is provided with means forming a gas passage
between the sample space of the tip and the cylindrical space of
the suction device.
12. The suction device according to claim 7, wherein the piston is
provided with a telescopically movable extension for moving the
removal means to the removal position.
Description
FIELD OF THE INVENTION
The object of this invention is a method for removing a replaceable
tip for use in a suction device for dispensing, transferring,
diluting, titrating, or mixing a liquid, or for a combination of
all or some of these operations.
The object of this invention is also a suction device for
dispensing, transferring, diluting, titrating or mixing a liquid,
or for a combination of all or some of these operations, which
suction device has an end part enclosing a cylindrical space having
a reciprocating piston for changing the volume of the cylindrical
space, the end part being provided with an aperture in the
extremity thereof intended for receiving a replaceable tip, in
order to form a gas passage between the sample space of the said
replaceable tip and the cylindrical space, and which has means for
removing the tip.
DESCRIPTION OF THE BACKGROUND ART
Since the 1970s suction devices have been in use, in which the
replaceable tip has been released and removed from the body with
mechanical means without the need to touch the replaceable tip by
hand. This is to avoid getting into contact with active and often
even dangerous chemical and biological samples and reagents. The
solutions have included mechanisms comprising levers or sleeves
which have been mounted upon the pipette body. These mechanisms,
which are known among others from the Finnish patent publications
56937 and 57540, have, however, increased the outer dimensions of
the body beyond the outer diameter of the replaceable tip. From the
U.S. Pat. No. 4,616,514 a suction device is known in which the
replaceable tip is attached to the body the end part having
finger-like strips provided with shoulders and in which the
replaceable tip is released with a moveable means mounted within
the end part acting on the finger-like strips. Also in this
solution the end part will be greater than the replaceable tip to
its diameter. In the development of diagnostic methods, nowadays
one strives at such methods, in which the volumes of the samples
and reagents utilized are increasingly smaller, which also leads to
the use of increasingly smaller sample tubes. The removal means for
replaceable tips mounted on the body of the suction device have
restrained the changeover to using small sample tubes and therefore
the removal devices have been removed from the suction devices. In
these cases the tips have to be removed manually, whereby the risk
for contamination again increases. There are also procedures in use
in which the replaceable tip is removed by means of a U-shaped
notch located in the side of a waste container.
In the following, the `suction device` stands for as such known
manual or electrical suction devices or pipettes, which are used
for pipetting, dispensing, diluting, titrating or mixing, or for a
combination of all or some of these operations.
The use of these suction devices in handling liquids, such as
samples or reagents, is described as a simplified example in the
following. Once a replaceable tip has been attached to the end part
of the body of the suction device and the piston moving in the
cylindrical space of the end part is brought to its home position,
whereby the piston is situated in the cylindrical space at that end
which is closest to the end part of the suction device, the
handling can be started. The outermost open end of the replaceable
tip is immersed into the liquid of which it is desired to take a
sample. When the piston is now moved inwards into the cylindrical
space, the change in the volume formed jointly by the sample space
of the replaceable tip and the cylindrical space brings about
suction of the sample or reagent into the sample space of the
replaceable tip. When it is desired to dispense the sample or the
reagent taken in this way into the tip, the piston is moved towards
the end part, whereby the said volume diminishes and at the same
time the liquid in the replaceable tip exits from the open end of
the replaceable tip. Several of these suction and dispensing stages
can be combined in succession to bring about the desired handling.
In these stages of sample handling the piston is moved to bring
about the desired suction or dispensing. In most cases as the last
stage the piston is moved past its home position mentioned above to
a blowout position so that the replaceable tip is completely
emptied. Thereafter the replaceable tip is removed from the end
part of the body of the suction device.
SUMMARY OF THE INVENTION
The object of the invention is to provide a method and a device
using the same for removing tips used in suction devices without
touching them manually. It is essential for this invention that the
means needed for the removal are at least mainly within the body of
the suction device and do not thereby increase the outer dimensions
of the end part of the suction device beyond the outer diameter of
the replaceable tip.
The method being the object of the invention is characterized in
that the replaceable tip is removed by bringing a removal means,
mounted in the air space formed jointly by the sample space of the
replaceable tip and the cylindrical space of the end part of the
suction device, which is movable between its two extreme positions,
namely an inner home position and an outer removal position, to
move into cooperation with an inside surface of the replaceable tip
mounted on the end part, whereby the movement of the removal means
into its removal position brings about the detachment of the
replaceable tip from the end part.
Bringing the removal means into cooperation with the inside surface
of the tip means that the movement of the removal means is
communicated to cause a removal movement of the replaceable tip
attached to the end part of the body of the suction device, e.g. by
bringing the removal means in contact with the inside surface of
the replaceable tip, or in contact with means associated with the
inside surface of the tip, such as projections, pegs, ribs, fins,
circular projections, or with means within the said air space
engaging the inside surface of the tip.
The removal of the tip in the method according to the invention can
take place so that the removal means in moving to the position for
removal, extends outside through an aperture in the end part into
the sample space of the tip into contact with the inside surface of
the tip, or with means associated therewith. According to an
alternative embodiment, the means in association with the inside
surface of the tip protrude into the cylindrical space of the end
part, and are brought there in contact with the removal means.
The method according to the invention is especially suitable for
the removal of such replaceable tips which are attached onto the
tip of the end part of the body of the suction device most
preferably with a friction joint. For the removal according to the
invention, such replaceable tips for attachment onto the tip of the
end part of the body of the suction device are advantageous, in
which the inside diameter of the sample space of the replaceable
tip tapers from the point of attachment towards the other end of
the replaceable tip. In these cases the removal means can in its
position for removal, according to one embodiment, be brought into
direct contact with the inside surface of the sample space of the
replaceable tip. Further the method according to the invention is
preferably suitable for the removal of such replaceable tips for
attachment onto the tip of the end part of the body of the suction
device, which in that end which is intended to be attached to the
body of the suction device, or in its vicinity, on the inside
surface of the replaceable tip are provided with projections, pegs,
fins, circular projections, transversal ribs or other similar means
or means within the sample space of the replaceable tip, over which
the removal means comes into contact with the replaceable tip in
its position for removal. In this case the removal means comes
preferably into contact with only such surfaces which have not been
in contact with the sample. When the removal means comes into
contact with the inside surface of the replaceable tip, with means
projecting into the sample space or with means within the sample
space, the movement of the removal means is communicated to the
replaceable tip and when the movement is substantially parallel
with the longitudinal axis of the replaceable tip, the replaceable
tip is made to detach from the end part of the suction device.
The movement of the removal means can be brought about by the
movement of the piston provided for changing the volume of the
cylindrical space of the end part of the body of the suction
device, whereby preferably the end of the said piston is brought
into contact with the removal means. In moving past its position
for blowout, the piston pushes the removal means out of the end
part of the body of the suction device and the removal means brings
about the detachment of the replaceable tip. According to an
alternative embodiment, the movement of the said removal means is
brought about by an extension part of the piston, e.g. a part which
is telescopically moveable with regard to the piston, whereby there
is no need to move the piston itself past the sample handling
positions.
According to a preferred embodiment, after the removal of the
replaceable tip, the removal means is returned to its home position
by a compression spring arranged in the cylindrical space of the
end part of the suction device.
The suction device according to the invention in turn is
characterized in that a removal means is arranged to move in the
cylindrical space of the end part of the suction device at least
partially between two extreme positions, namely between an inner
home position and an outer removal position. According to a
preferred embodiment, in the removal position, the removal means
can be brought to extend out of the aperture of the end part, into
the sample space of the replaceable tip mountable on the tip of the
end part, in order to remove the replaceable tip from the end part.
In its inner extreme position, in the home position, the removal
means is thus totally or almost totally within the cylindrical
space of the end part of the body of the suction device, but in its
outer extreme position, in the removal position, it extends outside
of the aperture of the end part of the body of the suction device
into the sample space of the replaceable tip, mountable on the end
part. In this removal position, the removal means comes into
contact with the replaceable tip, with the inside surface of its
sample space, with shoulders, ribs, fins or other similar means
protruding into the sample space, or with other means associated
with the inside surface in the sample space, whereby the
replaceable tip is detached from the end part of the body of the
suction device when the movement of the removal means continues in
the direction of the end part of the suction device and out of this
end part. According to an alternative embodiment, the removal means
is in its every position, thus both in its home position and in its
removal position, within the cylindrical space, and is brought in
the removal position into cooperation with shoulders, or other
corresponding means associated with the inside surface of the tip
and protruding into the cylindrical space.
In a preferred embodiment of the suction device according to the
invention, a compression spring is arranged in the cylindrical
space of the end part of the suction device between this end part
and the removal means in order to return the removal means back to
its home position after the removal of the replaceable tip. When
the removal means is in its removal position, the spring is
compressed and it is uncompressed in the home position for the
removal means.
According to an embodiment of the suction device, the removal means
and the piston, more specifically that end of the piston which is
nearest to the removal means, have at least two positions with
respect to each other, in one of which the piston in the sample
handling position is not in contact with the removal means, in its
home position, and in the second position, which compared to the
first one is a rotated position with regard to the longitudinal
axis of the piston, the piston at least in some sample handling
positions can be brought into contact with the removal means in its
home position. This is brought about by suitable mutual designs of
the piston and the removal means e.g. so, that the piston and the
removal means in the first of the said mutual positions are nested
or intermeshed without being in contact with each other and in the
latter of the mutual positions they are in contact with each other.
In this latter mutual position, the movement of the piston brings
the removal means to its removal position in some of the sample
handling positions.
Still according to one embodiment there is provided a spring or
spring-like means between the said piston and the removal means in
the cylindrical space, which spring or spring-like means in the
home position of the removal means is compressed and in the removal
position of the removal means is released or uncompressed. The
spring locks to its compressed state e.g. when attaching the
replaceable tip to the end part of the body of the suction device,
whereby at the same time the removal means is brought to its home
position. The said spring is preferably designed so that it due to
the locked state can remain compressed until an outside contact
releases the locked state. The release of the locked state is
brought about by the said piston or a telescopically movable
extension part thereof contacting the spring. When the locked state
of the spring is released the spring, when released, brings the
removal means to move to the removal position, whereby the
replaceable tip is detached from the end part of the suction
device. In a preferred embodiment according to the invention the
said spring can be a part of the removal means.
According to one embodiment of the invention, the removal means can
also be designed so, that it is a separate, as such easily
removable supplementary part, which can be removed from the end
part of the suction device. This is necessary in those cases, where
a possible carryover of samples or reagents by the removal means to
the next replaceable tip to be used must be avoided. The removal
means can be removed either at the same time with the replaceable
tip or after the removal of the replaceable tip either manually or
with the movement of the said piston.
In all of the embodiments of the suction device according to the
invention the removal means or respectively the shoulders or
similar means protruding into the cylindrical space from the inside
surface of the tip, are shaped so, that they allow a gas passage to
be formed between the cylindrical space and the sample space of the
tip. This can be realized e.g. by means of holes, channels, grooves
or other similar openings through the removal means.
According to an alternative embodiment of the invention, the
suction device does not have a separate removal means, but the
piston moving in the cylindrical space for changing the cylindrical
volume, or a part thereof, e.g. an extension part telescopically
movable with respect to the piston, acts as the said removal means.
The removal movement of the tip is brought about by moving the
piston past its blowout position to its removal position, or
alternatively by activating the extension part to move into the
removal position, into cooperation with the tip as described above.
In order to avoid contaminations in this case it is important that
the piston or its extension part comes into contact with only such
surfaces which have not been in contact with the samples. This
embodiment is advantageous especially in such an embodiment, in
which the removal means in each of its positions moves inside the
cylindrical space and in which the means associated with the inside
surface of the replaceable tip, such as projections, or other
similar means, in turn protrude into the cylindrical space.
Further scope of the applicability of the present invention will
become apparent from the detailed description given hereinafter.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art from
this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in following by means of examples with
reference to the enclosed drawings which are given by way of
illustration only, and thus are not limitative of the present
invention, and in which
FIG. 1 illustrates a longitudinal section of a suction device
having a removal means and a exchangeable replaceable tip,
FIG. 2 illustrates a section corresponding to FIG. 1 showing the
removal of the replaceable tip by means of the removal means,
FIG. 3 illustrates the replaceable tip with projections protruding
into the sample space,
FIGS. 4 and 5 illustrate the alternative embodiments of the removal
means, and
FIG. 6 illustrates a longitudinal section of such a suction device
having a spring-like means between the piston and the removal
means.
DETAILED OF THE PREFERRED EMBODIMENTS
In the FIGS. 1-6 the same reference numbers are used for parts
corresponding to each other. In FIG. 1 the end part of the suction
device is referenced with number 1, the replaceable tip adapted
onto the end part with number 2, its sample space with number 10
and the removal means with number 4. In the cylindrical air space 8
of the end part the piston 5 moves slidingly for changing the
volume of the cylindrical space 8. In the illustrated embodiment
the position 6a of the piston 5 is the home position of the piston
and the position 6b is the home position of the removal means 4.
The spring 7, which is mounted in the cylindrical space 8 between
the distal end of the end part 1 of the suction device and the
removal means, holds the removal means 4 in its home position 6b.
In its home position 6a the piston 5 is not in contact with the
removal means 4 in its home position 6b. When the replaceable tip 2
is to be detached, the piston 5 is brought to move past its home
position 6a, whereby the piston 5 first comes into contact with the
removal means 4, and the movement continuing, the piston 5 pushes
the removal means 4 and when this has come into contact with the
inside surface of the replaceable tip 2 or with shoulders,
projections or with means in the sample space 10 of the replaceable
tip 2, it detaches the replaceable tip 2 from the end part 1 of the
suction device. When the replaceable tip 2 is detached, the piston
5 is brought to move back to its home position 6a. The compression
spring 7 returns the removal means 4 to its home position 6b.
In FIG. 2 is illustrated the removal according to the invention of
the replaceable tip 2 from the end part 1 of the body of the
suction device with the removal means 4 being in its removal
position 6c. The figure also shows the aperture 9. which forms the
gas passage between the sample space 10 of the replaceable tip 2
and the cylindrical space 8.
In FIG. 3 is illustrated an embodiment of the replaceable tip 2
having a shoulder 3, protruding into the sample space 10, which in
cooperation with the removal means 4 brings the replaceable tip 2
to be detached in the position 6c of the removal means 4.
In FIG. 4 is illustrated an embodiment of the removal means 4
according to the invention, in which the removal means 4 remains in
its home position 6b by means of friction between the means 4 and
the wall of the cylindrical space 8, the friction, however, not
preventing the movement of the removal means 4. The removal means 4
is made of an elastic material, e.g. of plastic having suitable
characteristics. That part of the removal means 4 which extends
into the cylindrical space 8 is, in a preferred embodiment,
comprised of strips the ends of which extending into the
cylindrical space 8 being formed as tips so that the removal means
4 can easily be pushed through the aperture 9 into the cylindrical
space 8. The tips lean against the inner walls of the cylindrical
space 8 and hold the removal means 4 slidingly attached to the
cylindrical space 8. Due to the strip-like construction of the
removal means a gas passage is formed between the cylindrical space
8 and the sample space 10 of the replaceable tip 2.
FIG. 5 illustrates such a device according to the invention, in
which the removal means 4 in the example is formed so that the part
of the removal means 4 which extends into the cylindrical part
comprises both of longer strips 4b and of shorter strips 4c. The
removal means can be made of an elastic material, e.g. of plastic.
The ends of the strips 4b and 4c are formed into tips so that the
removal means 4 can easily be pushed through the aperture 9 into
the cylindrical space 8. The tips lean against the inner walls of
the cylindrical space 8 and hold the removal means 4 slidingly
attached in the cylindrical space 8. The end of the piston 5 is
respectively designed in a steplike fashion so that the piston in
its home position 6a is in such a position with regard to the
removal means 4 that the end of the piston 5 is not in contact with
the shorter strips 4c of the removal means 4 in the home position
6b of the removal means. When the piston 5 is brought sufficiently
further into the cylindrical space 8 with respect to its home
position 6a and after that it has been rotated around its
longitudinal axis e.g. 180.degree., when moving back towards its
home position 6a and possibly past it, it comes into contact with
the longer strips 4b of the removal means 4, whereby a continuation
of the movement brings the removal means 4 to move into the removal
position and the detachment of the replaceable tip 2.
In FIG. 6 there is illustrated a preferred embodiment of the
invention, in which there is a spring-like means 11 arranged in the
suction device in the cylindrical space between the piston 5 and
the removal means 4. This spring-like means 11 has such a
construction that it can be compressed and locked into this
compressed state. The locked state can be released by an external
contact, whereby the means 11 returns to its uncompressed state, in
which state the length of the means 11 is substantially greater
than the compressed length. This spring-like means 11 is
illustrated in the figure locked in its compressed state, whereby
the removal means is in its home position 6b. When the piston 5,
after having moved past also its blowout position, comes into
contact with the means 11, the locked state of the spring means 11
is released and the means 11, when being released to its
uncompressed state, causes the removal means 4 to move to the
removal position and the detachment of the replaceable tip 2.
In all embodiments the removal means 4 is designed so that it
allows a gas passage to be formed between the cylindrical space 8
and the sample space 10 of the replaceable tip 2, e.g. by means of
holes, channels formed in the removal means 4 and/or in its end 4a
nearest the replaceable tip 2, or by means of other similar
openings or grooves provided through the removal means.
The invention being thus described, it will be obvious that the
same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are intended to be included within the scope of the
following claims.
* * * * *